Research On Many-to-Many-Based Resource Allocation For D2D Communication In LTE-A System

People have put forward higher requirements on the delay,transmission rate and system capacity of traditional cellular networks with the rapid development of short-range social communication,wearable devices and vehicle networking in recent years.Therefore,3GPP introduced D2D communication technology for the LTE-A system to cope with the rapidly growing demand.The resource allocation of D2D communication is one of the focus of current research.The current research of D2D communication resource allocation is mostly based on one-to-one or one-to-many multiplexing methods between spectrum resources and D2D equipments.However,when the number of D2D pairs in the system is large or the demand for throughput is high,one-to-one or one-to-many multiplexing cannot fully meet the system requirements.In view of this problem,this thesis mainly studies the following aspects:To reduce the interference between users and improve system throughput,a hypergraph-based resource allocation scheme is proposed.Firstly,to avoid reusing of the same spectrum resources between users that are close in distance.Hypergraph is used to cluster the users in the system.Then a two-stage resource allocation scheme is used to ensure the quality of service of cellular users and cellular user's spectrum resources can be allocated to multiple D2D pairs.Besides,the spectrum resources of multiple cellular users can be occupied by a D2D pair.Simulation results show that the proposed algorithm can effectively improve the system throughput while ensuring the cellular user rate.The resource allocation of D2D communication is mostly based on the idea of greedy algorithm.Although the computational complexity of greedy algorithm is small,but it is easy to fall into the local optimal solution.To solve this problem,a D2D resource allocation scheme based on genetic algorithm is proposed.Firstly,the interference model is constructed according to the interference condition in the system,and the matching constraint matrix and the interference matrix are defined.Then,through the selection,crossover,mutation,genetic modification and elite retention process of genetic algorithm,iteratively selects the optimal matching matrix.The simulation results show that the proposed algorithm has a great improvement in system throughput compared with the resource allocation method based on the greedy algorithm.Due to the many-to-many multiplexing between D2D equipment and spectrum resources,the different channel quality of each D2D pair will cause the user to allocate a different number of spectrum resources.To ensure fairness in resource allocation process,a resource allocation scheme guaranteeing user satisfaction is proposed.The user satisfaction factor of D2D is introduced,with the goal of maximizing the weighted sum rate of the system,and the problem is solved through the fireworks algorithm.Simulation results show that the proposed algorithm can effectively improve the throughput of the system and satisfaction of D2D users.